Generally on a computer system, there is a single operating system (OS) running to manage computer resources such as a computer processor, a main storage unit (hereinafter, referred to simply as a main memory), a secondary storage unit, and a device of a computer, and schedule the computer so that the computer can operate efficiently.
OSs possess their own unique characteristics, including multi-functional OSs with a lot of properties such as Windows (registered trademark) and Linux (registered trademark), and real-time OSs having functions specializing in real-time processing.
Among others, a multi-operating system (multi-OS) is known to enable a plurality of OSs like those described above to operate on a single computer configured to have a single or a plurality of processors.
A multi-OS is described in Patent Literature 1, Patent Literature 2 and Patent Literature 3, for example.
Referring further to a multi-OS, with an interrupt generated via a peripheral device such as a mouse or a keyboard, an OS accepting an interrupt request is specified according to the interrupt number, and the interrupt number of the generated interrupt is determined, thereby switching OSs (see e.g., the technology disclosed in Patent Literature 1).
With an existing computer, peripheral devices are added.
However, there is a limit to the number of interrupt signals on the computer, and therefore the addition is not easy.
Accordingly, a single interrupt signal line is increasingly shared by a plurality of peripheral devices, like a group of peripheral devices connected to a peripheral component interconnect (PCI) bus.
Alternatively, interrupts from a plurality of peripheral devices are collected by a smaller number of interrupt management devices than the peripheral devices to share an interrupt signal line.
A PCI interrupt signal line (interrupt signal) is disclosed in Non-Patent Literature 1, for example.